# Permutations Combinations and Probability

User Generated

qf0002

Mathematics

## Description

A. For the Worksheet "Definitions and Word Problems-Part 1, Question 3 (Telephone numbers). I need an explanation of why the answer is 1/420. How do they get that.

B. For Test Form 1, I need explanations for the following problems:

Number 7-How did they get an answer of .79?

Number 8-How did they get an answer of 2/3? How do you solve this problem?

Number 10-How did they get an answer? Why is it correct?

Number 11-Why is a bar graph the correct answer?

Number 13-How do you solve this problem?

Number 14 How do you solve this problem?

Bonus-How do you solve this problem?

I think it will take far less than an hour to solve these problems.

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Hi again, You may find attached the solution to your homework explained. If you need something else do not hesitate to contact me again.YoursSpyros

A) Part 1 Question 3
We have seven numbers to be ordered in particular positions. For the
first place we have three 2s to select from seven numbers. So the
probability for the first number to be 2 is 3/7. As we have already put
the first number, we have six remaining "candidates" for the second
position. Now we have only two 2s available, as the trird one have been
placed on first position. So the probability for the number in second
position to be 2 is 2/6. Similar the probability for the number in third
position to be 2, is 1/5 (one remaining 2 and 5 candidates). Working in a
similar way, we have two 3s and four candidates for the fourth position.
So the pr...

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Anonymous
Great content here. Definitely a returning customer.

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